High dose gabapentin does not alter tumor growth in mice but reduces arginase activity and increases superoxide dismutase, IL-6 and MCP-1 levels in Ehrlich ascites.

OBJECTIVES: The purpose of this study was to evaluate the effect of gabapentin on Ehrlich tumor growth in Swiss mice, a highly aggressive and inflammatory tumor model. Mice were grouped into sets of 5 animals and treated from days 2 to 8 with gabapentin 30 mg/kg body weight (G30) or 100 mg/kg body weight (G100), or normal sterile saline (control). RESULTS: The mice were euthanized on day 10. Tumor growth, tumoricidal agents and inflammatory cytokines levels were assessed. At day 10, G30 and G100 mice gained weight, but there were no differences in tumor cell count or in ascites volume. In G100, there was a reduction in arginase and an increase in SOD activities. There was an increase in IL-6 and MCP-1 levels, especially in G100, but no alterations in TNF-α. There was no direct evidence of tumor induction by gabapentin. However, the findings suggest that its use modulates immune response to a more effector and less deleterious profile, with increase in activity of anti-oxidant enzymes and in cytokines that favor activation of macrophages, which could improve the general status of the tumor host.